Why “What Caused My Running Injury?” Is Often the Wrong Question

You get a pain in your knee after a run.

Your Achilles starts grumbling.

Or that calf problem you thought had gone suddenly appears again.

The natural question is:

What caused it?

Was it the new shoes?

The hill session?

Your running technique?

Weak glutes?

Running too far?

Sometimes there is a fairly obvious answer. If you trip, roll your ankle and immediately feel pain, there is a clear event to investigate.

But many running injuries do not happen like that.

They creep in.

You notice discomfort after a run. Then during the next one. Perhaps it settles again, then returns a week later.

In those situations, trying to identify one thing that “caused” the injury can send you in the wrong direction.

A more useful question is often:

What might have contributed to this problem developing, and what should I do about it now?

That small change in wording can lead to much better decisions.

Running injuries rarely have one simple explanation

Research into running injuries has investigated hundreds of possible factors:

Training volume.

Previous injuries.

Running technique.

Strength.

Footwear.

Sleep and recovery.

Training experience.

Health and lifestyle.

And plenty more.

Yet we still cannot reliably look at an individual runner and say:

“You developed this injury because of that one thing.”

A 2024 umbrella review combined 13 systematic reviews covering 148 studies and more than 200 different outcomes associated with running injuries.

Potential relationships appeared across training, health, lifestyle, biomechanics and physical characteristics.

But the quality of the evidence was generally low, with considerable differences between studies.

That means there are plenty of things worth considering, but far fewer things we can confidently call the cause of an individual runner’s injury.

A risk factor is not automatically a cause

Suppose research finds that runners with a particular characteristic get injured more often.

That does not automatically mean changing that characteristic will prevent injury.

It might genuinely contribute.

It might interact with several other factors.

Or it might simply be associated with something else.

This distinction matters because once runners are given a simple explanation, they often start trying to fix it.

They change shoes.

Change running form.

Start new strength exercises.

Stretch more.

Reduce their mileage.

Sometimes all at once.

If the original explanation was wrong, they may be solving a problem they never actually had.

The run where it hurt may not be the run that caused it

Imagine you complete a hard hill session on Tuesday.

Your Achilles hurts on Wednesday.

It is tempting to conclude:

The hill session injured my Achilles.

Perhaps it contributed.

But what had happened before Tuesday?

Maybe you had recently increased your weekly running.

Added faster sessions.

Started running hills again.

Returned after time off.

Changed shoes.

Added gym work.

Or been struggling to recover properly for several weeks.

The Tuesday session may simply have been when the symptoms became noticeable.

That is why I am usually more interested in the pattern leading into the problem than immediately blaming the final run.

Think about load and capacity

One useful way to understand many gradual-onset running injuries is to look at the relationship between the load being placed on the body and its current capacity to tolerate it.

Running is supposed to load your body.

That is how training works.

Muscles, tendons, bones and other tissues experience stress and, given suitable loading and recovery, adapt to it.

The problem is not simply:

Load = injury.

The question is whether the demand being placed on a particular part of the body is appropriate for what it can currently tolerate.

And that capacity changes.

A workload you handle comfortably while training consistently may be much harder after several weeks off.

A session that is manageable when well recovered may feel very different when fatigue has been accumulating.

An old injury may temporarily affect what an area tolerates.

Faster running can change the demands even when weekly mileage stays the same.

Strength training adds load too.

So instead of asking only:

What caused this?

I would also ask:

Have the demands being placed on this runner started to exceed what they are currently prepared to tolerate?

That gives us something useful to investigate.

There is no magic safe percentage

Running injuries are often blamed on doing “too much, too soon”.

There is some logic to that, but there is no universal weekly percentage that guarantees safe progression.

The familiar 10% rule is a guideline, not a proven injury-prevention threshold.

It also focuses heavily on mileage.

A runner could keep the same mileage while adding intervals, hills, racing or another hard session.

They could also increase their mileage gradually every week without ever spending enough time adapting to the previous increase.

That is why I would rather ask whether someone appears ready for more running than whether their spreadsheet says the increase is below an arbitrary percentage.

Shoes, strength and running technique can matter — but be careful with the story

These three things are common targets when runners become injured.

“It was my new shoes”

A big change in footwear may affect how load is distributed, so shoes can matter.

But pain starting shortly after buying new shoes does not prove the shoes caused it.

Perhaps the runner also increased training.

Perhaps the shoes were first worn for an unusually long run.

Perhaps discomfort had already begun.

The timing gives us something to investigate, not automatic proof.

“My glutes are weak”

Strength training can improve strength, performance and running economy, and building physical capacity can be very useful for runners.

That does not mean weakness was necessarily the original cause of an injury.

A 2024 systematic review of exercise-based injury-prevention programs in endurance runners found no significant overall reduction in injuries when the studies were combined, although supervised programs appeared more promising.

So I absolutely want runners to become stronger.

I just would not tell every injured runner:

“You got injured because you weren't strong enough.”

“My running form caused it”

Running mechanics can affect where and how forces are applied to the body.

But not every visible difference is a fault.

A 2023 systematic review examined hundreds of biomechanical variables associated with running injury. The prospective evidence was largely inconsistent.

That does not mean technique never matters.

It means seeing something unusual on a treadmill does not automatically tell us why someone became injured.

A movement pattern can be investigated when it is relevant to the actual problem.

That is very different from trying to make every runner look the same.

Previous injury deserves attention

One finding that appears reasonably consistently in running-injury research is that previous injury is associated with an increased likelihood of future injury.

That can be useful information.

Maybe rehabilitation was incomplete.

Maybe the runner returned to training faster than the area could tolerate.

Maybe the same conditions have appeared again.

Or perhaps it simply tells us that this area deserves a little more attention.

Previous injury is part of the context.

It still does not give us a complete explanation by itself.

So what would I actually look at?

If a runner came to me with a gradual-onset pain or recurring niggle, I would work backwards through the context.

What changed?

Did mileage increase?

Was more speed added?

More hills?

Another running day?

A return from a break?

New strength work?

Different shoes?

A change is not automatically the cause. It simply tells us where to start looking.

What was happening before the symptoms?

Was another area already sore?

Was recovery getting worse?

Had running started feeling unusually hard?

Had the runner recently been ill?

Was this a recurrence of an older issue?

Was there already some discomfort before the final session?

What does the problem actually look like?

Where is the pain?

When does it appear?

Is it worsening as the run continues?

Does it affect walking?

Is it becoming progressively worse?

Is it very localised?

Is the runner changing how they move because of it?

“Something hurts” is not enough information to make a sensible decision.

Which contributors are actually plausible?

You could probably create a list of twenty theoretical factors for almost any injury.

That is not useful.

The aim is to identify the small number that genuinely make sense for this runner, this problem and this point in their training.

What is the smallest sensible adjustment?

Not every niggle needs a complete shutdown.

Continuing unchanged is not always sensible either.

Depending on the problem, the first adjustment might be reducing volume, changing intensity, replacing one session, allowing more recovery or temporarily avoiding a particular stimulus.

The aim is not to panic.

It is to respond early enough that you still have options.

Do not change everything at once

Once a runner decides they have found “the cause”, it is easy to change several things together.

New shoes.

Different cadence.

New strength exercises.

More stretching.

Less running.

No hills.

If the pain improves, you have no idea which change mattered.

If it worsens, you have the same problem.

Where it is safe to do so, I would rather make the most sensible adjustment, observe what happens and keep gathering information.

Real training creates new information.

Good coaching responds to it.

Sometimes you need an assessment, not another theory

A coach should not try to diagnose every pain.

Some problems deserve appropriate medical or clinical assessment.

Severe or worsening pain, difficulty bearing weight, significant swelling, numbness after an injury, an obvious deformity, or feeling unwell with a hot and swollen joint all warrant medical attention.

Persistent, very localised bone pain also deserves caution because bone stress injuries can develop without one dramatic traumatic event.

And if the same problem repeatedly returns despite sensible training adjustments, that is a good reason to stop guessing and have it properly assessed.

COACH'S DECISION

If a gradual-onset pain or recurring niggle appears, I would not begin with:

“What single thing caused this?”

I would ask:

What changed recently?

What might already have reduced this runner's capacity?

Which contributors are genuinely plausible?

What is the safest useful adjustment to make first?

Is there anything here that needs professional assessment rather than coaching guesswork?

The goal is not to identify the perfect culprit.

The goal is to make a better next decision.

You may never know exactly what caused it

That can feel frustrating.

People like clear explanations, particularly when something has stopped them running.

But false certainty is not especially useful.

Telling someone their pain was definitely caused by their shoes, weak glutes, overpronation or one hard session might provide a simple answer.

It does not necessarily provide the right one.

Sometimes one factor will stand out.

Often several things may have contributed.

Sometimes we simply will not know.

You do not need a perfect explanation of the past before you can make a sensible decision about what happens next.

Want a better way to look at your running?

Running problems rarely sit neatly inside one box.

Training, technique, strength, mobility, recovery, nutrition and mindset can all be part of the wider picture — although that does not mean every area is responsible whenever something hurts.

My free 7 Core Pillars™ Guide explains the areas I consider when helping runners make better training decisions.

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